To update your Rubygems to the latest available version, type the following:

 gem update --system

Note that you have a separate Rubygems installation for each Ruby version in your RVM or rbenv setup. Updating one does not update the others.

Ruby 1.8.7

If you are using Ruby 1.8.7 you cannot use the latest version of Rubygems. Type the following to get the latest version that is compatible with 1.8.7:

 gem updat...

You can make both mobile Chrome and mobile Safari display a native app install banner. The banner suggests that the user installs an app that is related to the current page. It is shown in the phone's native UI. See attached animation.

There is some fineprint you need to read to make this work (see below).

References

• Android: Increasing engagement with Web App install banners
• [iOS: Promoting Apps with Sm...

Interesting talk about a team that integrated automated security testing into their BDD workflow.

There is also a video of the talk.

Unfortunately, Web APIs haven’t provided the functionality to copy text to the clipboard through JavaScript, which is why visiting GitHub with Flash disabled shows an ugly grey box where the button is supposed to be. Fortunately, we have a solution. The editor APIs provide document.execCommand as an entry point for executing editor commands. The "copy" and cut" commands have previously been disabled for web pages, but with Firefox 41, which is currently in Beta, and slated to move to release in mid-September, it is becoming available to Ja...

I am happy to announce that this information is now available in JSON form at https://ip-ranges.amazonaws.com/ip-ranges.json. The information in this file is generated from our internal system-of-record and is authoritative. You can expect it to change several times per week and should poll accordingly.

If you'd like to preview the crontab that whenever will deploy, run the following:

bundle exec whenever

This will print the cron syntax without modifying your local crontab.

You may encounter problems with passenger starting an application with an updated rails.
If you find an error like this in the apache error log:

[ 2015-08-21 10:53:04.1266 17680/7f4909bf7700 Pool2/Implementation.cpp:883 ]: Could not spawn process for group /var/www/example.com/current#default: An error occured while starting up the preloader.
     in 'void Passenger::ApplicationPool2::SmartSpawner::handleErrorResponse(Passenger::ApplicationPool2::SmartSpawner::StartupDetails&)' (SmartSpawner.h:455)
     in 'std::string Passenger::Appli...

If you need a postgresql extension for your database it isn't a good idea to give your applications database user superuser rights (like many people on stackoverflow think)

Just login to the database with a superuser account (e.g. postgres) and create the extension with it.

Example:

# with the default configuration of postgresql you normally can login as `postgres` user
# without a password if you use the systems `postgres` user
$ sudo su -l postgres
$ pgsql
postgres=# \c your_database;
psql (9.3.9, server 9.3.5)
You are now connected...

You can include files from app/assets or from the public folder with javascript_include_tag. The subtle difference that tells rails how to build the path correctly is a single slash at the beginning of the path:

<%= javascript_include_tag('ckeditor/config') %> # for assets/ckeditor/config.js
<%= javascript_include_tag('/ckeditor/ckeditor') %> # for public/ckeditor/ckeditor.js

This also applies to stylesheet_link_tag.

Note that when you refer to a Javascript or stylesheet in /assets you need to add it to [the list of asse...

rbenv

To check which rubygems versions your different rbenv rubys are using, you can use this small bash script:

for i in $(rbenv versions --bare); do rbenv shell "${i}"; echo -n "ruby ${i} has gem version: "; gem -v; done

RVM

rvm all do gem -v

As you most likely know validates_uniqness_of :foreign_id does not allow nil values by default.

To allow nil one has to set the :allow_nil => true option.

Very unexpected scoping this validation will not raise an error if foreign_id set to nil for the first created record of this kind.

validates_uniqueness_of :foreign_id, :scope => :another_column # allows foreign_id to be nil

Without a validation for presence of foreign_id now unusual records could be created.

tl;dr

• Use form models to handle this problem
• Or soften the validation to validates_presence_of :parent

Usually you would validate presence of parent object id, like in this example:

class Parent < ActiveRecord::Base
  has_many :nested, :inverse_of => :parent
  accepts_nested_attributes_for :nested
end

class Nested < ActiveRecord::Base
  belongs_to :parent
  validates_presence_of :parent_id # <- 
end

With the parent already persisted creating nesteds still works fine.

But one will encounter a *'parent id missing' er...

Each time thin boots, it prints a boot message :

Thin web server (v1.6.3 codename Protein Powder)
Maximum connections set to 1024
Listening on localhost:36309, CTRL+C to stop

If you are running parallel tests with thin, this will clutter you output. Disable thin logging with these lines:

# e.g. in features/support/thin.rb

require 'thin'
Thin::Logging.silent = true

Note that this disables all logging in tests. Instead, you also might set a different logger with `Thin::Loggi...

If you hover over the text of a card, you will now see EDIT links at the top right corner of each block.

This link will open the card editor and scroll the editor to this very paragraph. The cursor caret will sit on the first character of that paragraph.

This should help making small changes to longer cards.

A word of caution

There should rarely be a reason for you to split up config/routes.rb. If you need to, probably your whole application should be split up.

Split it anyway

Rails::Engine looks at config.paths['config/routes.rb'] and registers its value with app.routes_reloader. This means you could put routing files anywhere and then require them. However, I recommend to put any routing files into config/routes/:

# config/routes/example.rb

Rails.application.routes.draw do
 resources :example
end

After creating y...

MarcoPolo shows your app name and environment in your console prompt so you don't accidentally break production
Officially supporting IRB (standard rails console) and pry (via pry-rails gem).

Example:

$ rails console
Loading development environment (Rails 4.2.1)
agencyapp(dev)> 

Use base_class.

This traverses up the hierarchy until it encounters either

• a class inheriting from ActiveRecord::Base or
• a class inheriting from an abstract class (inheriting from ActiveRecord::Base)

Here is how to start your Rails application to accept both HTTP and HTTPS in development.

1. gem install passenger

2. Create a self-signed SSL certificate. Store the generated files in config/passenger-standalone-ssl.

3. Create a Passengerfile.json at the project root with this content (or save the attached file):

   {
     "ssl": true,
     "ssl_port": 3001,
     "ssl_certificate": "config/passenger-standalone-ssl/server.crt",
   

   ...

Reason: You very likely have a model that has a delay attribute.

You can configure Sidekiq to remove its delay method by adding this to your Sidekiq initializer:

Sidekiq.remove_delay!

If you need to keep Sidekiqs delay features, add Sidekiq.hook_rails! before the option above. The sidekiq methods will be prefixed with sidekiq_ then.

Free Bootstrap theme resembling Material Design.

Bootswatch offers Sass and Less files, so the theme can easily be integrated into your usual Rails application.

Implements only Bootstrap features which means that some Material stuff is missing, but also that you can easily use or replace the theme.
Does not come with extra JavaScript; some effects like button click ripples are implemented via CSS.

Also check out their other themes which can be used in a similar fashion.

Navigation

CTRL + SHIFT + ALT + N

Search for any symbol in your application, like CSS classes, Ruby classes, methods, helpers etc.

CTRL + SHIFT + N

Search for filename in your application (also dependencies)

CTRL + E

Open a list of recently opened files

ALT + POS1

Open a the navigation bar as a context menu. Allows you to quickly navigate between files.

CTRL + G

Go to line

Actions

CTRL + SHIFT + A

:...

In tests, it is sometimes useful to create records with specific ids. On PostgreSQL this can cause problems:

Usually, PostgreSQL uses an "autoincrement" sequences to provide sequential ids for new database rows. However, these sequences will not increment if you insert a record "by hand". This will cause an error:

record = Record.create!
record.id                             # => 100, next automatic id will be 101
Record.create!(id: record.id + 1)     # okay, but next automatic id will still be 101
Record.create!                       ...

Interesting hack to move expensive JSON.parse calls out of the main thread.

To change RAM size, VDISK size or VCPU count of an openstack instance you have to use nova resize. You can't change for e.g. just the RAM size with a parameter, you have to assign a new/other flavor. If there is no suitable flavor for the new properties of the VM, create a new one.

nova resize [--poll] <server> <flavor>

The resize could take a while, after it is finished, the VM boots up with the new specifications. SSH into the VM and check if everything is alright...